Fuel burner control means



FUEL BURNER CONTROL MEANS Filed May 9, 1942 2 Sheets-Sheet 1 1s 9 w \L'x,

FIG: 1

INVENTOR '1) ATTORNEY y 1945- E. J. DOUCET 2,379,565

FUEL BURNER CONTROL MEANS Filed May 9, 1942 2 Sheets-Sheet 2 INVENT0RDBY 7 K M MATTORNEY be employed to regulate 3-4 of Fig. 2 looking in Iarrows,,and n 'Fig. 4 is a detail view in end elevational looking fromrightto left facing Fig. 3.

[ing an airinlet opening 1.] v

chamber I {and bonnet 4 there is a cylindrical Patented July 3, 1945UNITED; TA E s PATENT omen FUEL BURNER CONTROL MEANS Edward J. Doucet,Detroit, Mich, asslgnor to Detroit Lubricator Company, Detrolt,l\flch.,a corporation of Michigan AppllcationMay 9,1942,SerialNo-.442,290 9Claims. (chess-1o) This invention relates to new and useful improvementsin heating'apparatus and more par- 7 ticularly to safety means forcontrolling the operation of the burner of the apparatusin the event anundesirable high temperature of the apparatus should occur.

The invention is particularlv adaptedfor use in connection withfloorfurnaces wherein the outlet for the heated air might be obstructed as,

for example, by the placing of arug over the same and which wouldtherefore result in a dangerous temperature of the heating apparatus,

presenting a fire hazard. It is therefore one obiect ofthis invention toprovide novel means which will be certain in operation forjshutting downthe burner in the eventthe temperature ofthe apparatus reaches anundesired high degree.

Another object of the invention isto provide I a, safety means whichisparticula'rly adapted for use with the control means of gravity fedliquid fuel burners.

--VAnother'objectis to provide a construction in which a singletemperature responsive means burner by controlling fuel flow and also toactuate the safety means.

The invention consists in the cooperative relation and in theconstruction of parts which is more fully described hereinafter and thenovelty of which will be articularly pointed out and distinctly claimed.7 n

In the accompanying-drawings to be takenas a part of this specificationthere is fully and clearly illustrated a preferred embodiment of-theinvention in which drawings: v v

Figure 1 is a viewin vertical central section of afloor furnace havingthe safety control means of this invention operatively related thereto;

Fig.2 is a top plan viewof the control device Fig; 3 is a view invertical section on the line the direction of the In the accompanyingdrawings, the numeral designates generally a floor furnace type ofheating apparatus mounted upon a base 2 which may be the cellar floor.Within thefurnace there 'is a combustion chamber land a combustionproducts outlet 2" and an air heating bonnet 4. The combustion chamber 3has a fluid fuel burner 5 positioned in an air supply duct 6 havthe theoperation of the let to the upflow duct 8*.

partition 8 for air to be heated and having an outlet opening 9 througha grill forming part of the floor ll of the space |2 to be heated'by-theapp ratus- The furnace jacket "surrounds and is spaced from thepartition! and cooperates therewith to provide a downflow-passage l4 forair to be heated. 'The passage l4 has its inlet l opening through thegrill I0 from the room or space-l2 and" communicates atits. lower oroutlet end through an annular chamber IS with the ,in-

Positioned in the chamber l6v there is a con- 'stant liquid level devicel1 supportedby partition 18. Liquid fuel is supplied to the device-l1through an inlet pipe or conduit l9 leading from a supply tank "(notshown) and is-fed to the burner 5 through a--pipe or conduit leadingfrom the device l1. 1

The device H has a constant level chamber 2| provided by a casing 22having an inlet passage 23 connected to the conduit or pipe l9.-The.pas-

sage 23 discharges into the chamber 2| through an inlet port controlledby a float operated valve 24 controlled by a float-actuator 25, as is"well known in the art. Cooperable with the valve.

there is a safety mechanism" 28 having a lever 21 for moving the valve24 to closed position upon the occurrence of excess liquid level in thechaman helical coil spring 29 which is' held under 7 her 2|. The-lever21 is'pivotally supported at 28 and is urged toward valve closingposition'by compression between an end portion or arm 30 of thelever anda'bracket 3| carried by the easing 22. The lever 21 has an endportion 32'extending external of the casing 22 through a slot 32 in the casingwall. Secured on the'lever 21 adjacent the end portion l2there is alatch plate 34 which seats on the lip 35 of a trip lever-36 to holdthelever 21 against the valve closing movement by the spring 28.The'spring -29 which is in a slightly overcenter downward position'holdstheplate l4 in'engage'mentwith the lip. The

lever 36, pivoted at 31, has an arm 38 positioned for engagement by anextension 39 on-the lever 40 having a counter-weight 4|i'and whichinterconnects the fioat 25' and inlet valve 24. The lever 88 has a triparm 4 l'which extends through the slot 33 to the exterior of the casing'22 and which is positioned above the lever end portion 32 so that thearm 4| can be moved downward to I release the latchplate 24 withoutinterference with the lever extension 22. It may benoted that thebearing for the float arm 40 isprovided with lost motion so'thatthefloa't can have overtravel l providingan upflow passage orvduct .tionof the shaft 6i. normally held against. a stop member or lug 64 uponresistance to closing movement of valve 24 in order for the float torespond to excess liquid level and move the extension 36 into trippingen- I the thermostatic means 66 to wind up and move the metering valve43 to its low flow position for pilotflame at the burner 6. When thetemperature of the return air entering chamber I6 from passage I4decreases, showing a demand for heat in the space I2, then thethermostatic means 66 will'unwind in accordance with the decreasingtemperature and rotate the lever 62 upward or clockwise facing Fig. 4.Accordingly,

the metering valve 43 will move toward open 4 position under force ofthe spring 44, thereby stem 46 of the valve member 43. The stem 46extends upward-through a guide aperture 41 in the cover member 46 of thecasing 22.

Mounted on the top face of the cover mem ber 46 there are longitudinallyspaced bearing brackets 46, 66 through which there is journaled anoperating shaft 6|. Joumaled on the shaft II in overlying relation tothe valve stem 46, there is an operating lever 62 which is engageablewith the top end of the stem 46 to move the valve member toward closedposition against the forceof spring 44. The lever 62 carries anadjustable stop member 63 in the form of a screw which is engageablewith the top face of the cover member 46 to limit downward movement ofthe stem actuating end of the lever 62 thereby to determine the extentof valve closing movement and to determine the minimum flow position. ofthe valve member 43 for maintaining a pilot or low flame in the burner6. Opening movement of the valve member 43 is determined by a maximumflow adjustment screw' 64 which is adjustably screwthreaded in anextension 66' of the bracket 49 and which has its bottom end engageablewith the top face of lever 62 to limit its upward movement andthereforethe extent of upward movement of the valve member 43. The lever 62 isoperated by thermostatic means 66, preferably a helical coil bimetalstrip which surrounds the shaft 6| and has one end secured as at 61 tothe lever 62 and its other end 66 secured to the shaft 6I through afriction slip clutch 66. The bimetal coil 66 tends to coil up moretightly on temperature increase and therefore with the coil. end .66held against movement, the end 61 will rotate face 62 engageable withthe upper horizontal edge of the arm 4I. Aspring 63 anchoredat one endto the cam member 6| and its other end .to the cover member 46 is undertension to resist operation of the cam member 6| and rota- The cammember 6| is on the cover member 46 by the spring 63 and is limited inits clockwise tripping movement (facingFig. 4) by a stop member or lug66 carried by the cover member 48.

The operation of the apparatus is as follows: Assuming that the burner 6is operating to supply heated air through the outlet 6 to the space l2,the control device is shown in Figs. 3 and 4 in the position wherein thetemperature of the room or space has reached the desired predetermineddegree so that the return air in duct l4 to which the thermostat means-66 is subjected has caused supplying fuel with a greater flow rate tothe humor 5t0 provide'the necessary high flame for heating the space I2.This movement .of the lever 62 will occur since the cam member 6I isagainst the stop member 64, and therefore the shaft 6I is held againstrotation by the thermostatic means 66. As long as the grill I6 issufficiently unobstructed so that a proper and adequate circulation ofair can take place through the return and heating ducts I4, 6respectively, the thermostatic means 66 will act to maintain a desiredtemperature in the space I2. If, however, the grill It should be coveredas by the placing of a rug thereover, for example, and suflicient toprevent proper circulation of air to be heated through the furnace I,then the temperature in the chamber I6 will increase to the maximumreturn air temperature at which thermostatic means 66 moves the valvemember 43 to pilot flow position, as shown in Fig. 3. Since the airheated by the pilot or low burner flame and heated by the residual heatin the combustion chamber 3 and bonnet 4 is trapped in the furnace I,the temperature in the chamber I6 will rise rapidly above thepredetermined temperature to which valve member 43 is moved to minimumopen position. The thermostatic means 66 will accordingly exert anincreased force and since the coil end 61 is now held against movement,this increasing force will act through the coil end 66 to rotate theshaft 6I clockwise facing Fig. 4, thereby moving the camsurface 62across the projecting arm 4I of the trip lever 36 and by its cam actionrotating the trip lever clockwise facing Fig. 3 aboutits pivot 31. Thismovement ofthe trip lever 36 will 'release the spring 29 so that thesafety mechanism '26 will move the inlet valve-24 to full closedposition. The quantity of oil or liquid fuel remaining in the chamber 2|will continue to flow to the burner '6 but with a decreasing headpressure so that the flame in the burner 6 will gradually decrease andbecome extinguished in a relatively short time period. Accordingly, firehazard will be eliminated by extinguishment of the burner. In order torestart the burner, it is necessary after the cam member 6| has beenretracted to the position of Fig. 4 by cooling of the thermostatic means66; to manually lift the lever extension 32 until the latch plate 34again rests on the lip 36 as shown in Fig. 3. oil'will now again bepermitted to flow'to the burner 6 and may be reignited in the usual wayto again place the heating apparatus in operation.

Having thus described the invention, what is claimed and is desired'tobe secured by letters Patent of the United states is: r

1. In a heating apparatus, a fluid fuel burner, means for supplying fuelto said burner, a longitudinally slidable metering valve for regulatingthe supply of fuel, a safety valve operable to stop the supply of fuel,a spring urging said metering valve toward open position, thermostaticmeans responsive to the temperature of a medium heated b aid burner,means operatively connecting said valve toward closed position; force,exertingmeans tending to move said safety valve to closed posiii'igmeans against movement, means actuated by said thermostatic means torelease said releasable means, means to limit closing movement of saidmeteringvalve by said thermostatic means thereby to maintain a'reducedburner flame, and a spring opposing operation of said releasable meanswith a force greater than the force of said metering valve spring sothat an increase in temperature of said medium above the temperature atwhich said limiting means opposes said metering valve is required foroperation of said releasable means by said thermostatic means.

2. In a heating apparatus, a liquid fuel burner.

a constant liquid level device having a float operated inlet valve andan outlet to said burner, excess liquid level operated safety means formoving said inlet valve to closed position, a metering valve controllingsaid outlet and movable between thermostatic means to said meteringvalve so thatupon {temperature increase of said medium, saidthermostatic means willv-move said -meteringsaid metering valve to saidminimum positionv tion, releasable means holding said for'ce'exertmaximum and minimum open positionsto .pro-

vide highand low burner flames, thermostatic means mounted on saiddevice and responsive to the temperature of a, fluid medium heated bysaid burner, means operatively connecting said thermostatic means tosaid metering valve to move said metering valve to minimum position uponoccurrence of a predetermined high temperature of said medium, meansoperable by said thermostatic means to actuate said safety means, andmeans opposingoperation of said safety means by said thermostatic meanswith a force suflicient to require a temperature increase of said mediumabove said predetermined temperature prior to operation of said safetymeans by said thermostatic means. i 3. In a heating apparatus, aconstant liqui level device having an outlet for supplying fuel to aburner, a'vertically slidable metering valve,

controlling said outlet, safety means for stopping said safety means.

betweenthe highstemperature formovement of and the increased temperaturefor actuationof 5. Ina heating. level device having an inlet and havingan outlet for supplying fuel toa burner, a' float operated valvecontrolling .said inlet to maintain. a substantially constant liquidlevel. a safety lever en-- gageable with and operableito ,seat saidvalve, means urging said lever in a valve seatingdirection, a latchholding said lever against movement by said urging means, float operatedmeans engageable with and operable to release said latch upon occurrenceof liquid level above said constantlevel, a meteringvalve controllingsaid outlet, thermostatic meanspperable to move said meteringvalve-toward closed position, and means operable by said thermostaticmeans to release said latch.

, 6. In a heating apparatus, a constant liquid level device having aninlet and having an outlet for supplying fuel to a burner, a floatoperated valve controlling said inlet to maintain a. substantiallyconstant liquid level, a safety lever en,-

' gageable with, and operable to seat said valve,

the admission of fuel to said device, an operating shaft rotatablymounted on said device, a lever Journaled on said device and operable toactuate said metering valve, a bimetal coil thermostatic means havingone end secured to said lever and having its other end secured to saidshaft, means mostatie means to actuate said safety-"means,

and means resisting rotation of said shaft bylsaid means urging saidlever in a valve seating direction, a latch holding said lever againstmovement by said urging means, float operated means engageable with andoperable to release said latch upon occurrence of liquid level abovesaid constant level, a metering valve controlling said outlet,thermostatic means operable to move said metering valve toward closedposition, means to limit closing movement of said metering valve,

means operable by said thermostatic means to.

release said latch, and means requiring an increased temperature of saidthermostatic means to operate said last-named means subsequent tooperation of said limiting means.

7. In a heating apparatus, a constant liquid level device having achamber with an inlet and 1 with an outlet for supplying fuel to a.burner, a valve controlling said inlet, meansresponsiveto liquid levelin said chamber and operatively connected tosaid valve to maintain -asubstantially constant liquid level in said chamber, safety meansoperable to move said valve to closed position, means operableto'actuate said safety means operable upon rotation of said shaft by saidtherto close said valveuupon occurrence of a liquid 4. In a heatingapparatus;a floor furnace havi'ng inlet and outlet openings for returnand for flow of heated air from and to the space to be heated, a liquidfuel burner for heating the air supplied to said outlet opening, aconstant liquid level device an inlet and having an. outlet forsupplying fuel to said burner. a" float operated valve controlling saidinlet, a metering valve conftrolling said outlet, safety means to closesaid inlet valve for stopping the admission of fuel to said device,thermostatic means responsive to the temperature of said furnace, meansdirectly and positively mechanically connecting said thermostatic meansto said metering valve, said ther mostatic means moving saidmeteringlvalve toja minimum flow position at a predetermined highfurnace temperature, means directly operable by the force of saidthermostatic means at an increased temperature above said hightemperature metering means controlling flow from said outlet,

thermostaticgineans operable to actuate said metering means, andmeansoperable by said thermostatic'means to actuate said safety means toclose said valve.

8. In a heating apparatus, a constant liquid level device having achamber with an inlet and with an outlet for supplying fuel to a burner,a valve controlling said inlet, means responsive to liquid level in saidchamber and operatively connectedto said valve to maintain asubstantially constant liquid level in said chamber, safety meansoperable tomove said valve to closed position, means operable to actuatesaid safety means to close, said valve upon occurrence of a liquidlevel'in said chamber above said constant level, metering meanscontrollingflow from said outlet,

thermostaticsmeansresponsivew tmperature of a medium heated-by theburner and operableto actuate said metering meansto reduce now-fromsaidoutlet upon temperature increase of the 'medium, means operable by saidthermostatic meansto actuate mechanically smashes 'meanaiandeansdetermining the temperature differential apparatus, a constantliquid.

in; means operable by saidactuated means to actuate said safety means. ametering valve controlling tiow from said outlet, thermostatic meansoperable to actuate said'metering valve. means to limit closing movementof said metering valve by said thermostatic'means, means 101' continuedmovement of said thermostatic means upon temperature increase above thetemperature at which said metering valve is limited by said limitingmeans. and means operable by such continued movement of saidthermostatic means and operable to actuate said releasing means therebyto shut said inlet valve. 7

EDWARD J. DOUCET.

